1. Field of the Invention
The present invention relates generally to a floor sweeper of manual type, and more particularly to a floor sweeper of the type, in which two parallel roll brush brooms are made to rotate inwardly by means of gear trains accommodated in two juxtaposed housings of enclosed type.
2. Description of the Prior Art
As is well known in the art, most of the conventional floor sweepers of manual type have employed one brush brooms, with the resultant drawback that the dust on the floor can not be swept up completely. In order to eliminate this drawback, an improved floor sweeper has been developed using two brush brooms, as in Japanese Patent Publication No. 72 - 10679 or in Japanese Utility Model Publication No. 71 - 9329. With these developments, the above problem has been solved tentatively.
In the invention of Japanese Patent Publication No. 72 - 10679, however, such new drawbacks come out that the sweeping performance is deteriorated abruptly as a result of wear of the wheels due to use for a prolonged time period because the roll brush brooms are made to rotate by their frictional engagements with the wheels, and that the floor sweeper can not sweep up the dust of smaller size on the floor because its roll brush broom at the rear side is rotating above the floor although the front broom is rotating on the floor. This deterioration in the sweeping performance is not effected in the floor sweeper of Japanese Utility Model Publication 71 - 9329, since its roll brush brooms are made to rotate by means of a gear mechanism. In this floor sweeper, however, one roll brush broom is driven by a single wheel, and the resistances to the front and rear brooms are varied at all times. Thus, such an unbalanced condition is established as is effected in the unbalanced braking effect on an automobile or the like, with the resultant new drawback that the floor sweeper can not run stably. Since, moreover, the gear mechanism is not accommodated in an enclosed housing, it often becomes inoperable due to invasion of the dust. Especially, since the main shaft supporting the two wheels is positioned above the roll brush brooms, the waste pieces of thread, which are swept up by the brooms, are liable to twine themselves about the main shaft, as in the other conventional floor sweepers. The resultant drawbacks are that the roll brush brooms are damaged and that the main shaft is prevented from rotating smoothly.